Nitride semiconductor light emitting device and method of manufacturing the same

ABSTRACT

A nitride semiconductor light-emitting device including a reflecting layer made of a dielectric material, a transparent conductive layer, a p-type nitride semiconductor layer, a light emitting layer and an n-type nitride semiconductor layer in this order and a method of manufacturing the same are provided. The transparent conductive layer is preferably made of a conductive metal oxide or an n-type nitride semiconductor, and the reflecting layer made of a dielectric material preferably has a multilayer structure obtained by alternately stacking a layer made of a dielectric material having a high refractive index and a layer made of a dielectric material having a low refractive index.

This nonprovisional application is based on Japanese Patent ApplicationNo. 2008-201971 filed on Aug. 5, 2008 with the Japan Patent Office, theentire contents of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a nitride semiconductor light-emittingdevice and a method of manufacturing the same.

2. Description of the Background Art

A nitride semiconductor light-emitting device having a one-sidetwo-electrode structure obtained by stacking an n-type nitridesemiconductor layer, a light emitting layer, a p-type nitridesemiconductor layer and the like on an insulating sapphire substrate andarranging a p-side electrode and an n-side electrode on such amultilayer structure is known in general. In the nitride semiconductorlight-emitting device having such a one-side two-electrode structure,however, the electrodes are not formed on symmetrical positions of theupper and lower surfaces of the chip, and hence luminous intensity isnot uniformized in plane, but emission concentrates on the p-sideelectrode or the n-side electrode. Further, it is difficult to increasethe size of the chip and the chip is easily deteriorated by aging due tothe aforementioned problem. In addition, the pad electrodes provided onone surface occupy large ratios in the surface area of the chip, and itis also difficult to reduce the size of the chip.

In order to solve the aforementioned problems, Japanese PatentLaying-Open No. 2001-244503, for example, proposes a method ofmanufacturing a nitride semiconductor light-emitting device includingthe steps of successively growing an n layer made of a galliumnitride-based semiconductor, a gallium nitride-based semiconductoractive layer and a p layer made of a gallium nitride-based semiconductoron a substrate, successively forming a p-side ohmic electrode such as anNi—Pt electrode, for example, and a first conductive adhesive layer madeof Au—Sn on the p layer, bonding a conductive substrate prepared bysuccessively forming a layer made of Au and a second conductive adhesivelayer made of Au—Sn to the above-mentioned substrate by bonding thesecond conductive adhesive layer and the first conductive adhesive layerto each other and separating the substrate and a nitride semiconductorlight-emitting device having a vertical electrode structure obtained bythis method. In the nitride semiconductor light-emitting devicedescribed in this document, however, light extraction efficiency isinferior due to low reflectance of the electrode.

A structure employing a distributed Bragg reflector (DBR) is known as adevice structure for improving light extraction efficiency. For example,National Patent Publication Gazette No. 2007-536725 discloses a methodof manufacturing a semiconductor device by forming an n-type GaN layer,a multiple quantum well (MQW) layer and a p-type GaN layer on a sapphiresubstrate in this order, thereafter forming a p-type contact layer onthe p-type GaN layer with a p-type contact metal such as Ni/Au, forminga DBR layer made of indium tin oxide (ITO) thereon and thereafterforming a support substrate by plating. In this structure, however, thelight extraction efficiency is not sufficiently improved due to largelight absorption by the contact metal such as Ni/Au. Further, whilelight absorption by ITO is negligible when the thickness of the DBRlayer is about 300 nm, the light extraction efficiency may beinsufficiently improved due to large light absorption if a thick filmsuch as a multilayer film is prepared from ITO in order to form the DBRlayer. While this document discloses no specific method of preparing theDBR layer from ITO, it is difficult to increase refractive indexdifference if a low refractive index layer is made of a materialidentical to that for a high refractive index layer, and the reflectanceof the DBR layer made of ITO cannot be increased as a result.

Japanese Patent Laying-Open No. 2003-234542 discloses a nitride-basedresonator semiconductor structure including a DBR, having a dielectriclayer obtained by alternately stacking an SiO₂ layer and a Ta₂O₅ layer,formed on a p-type contact layer with a thickness of a quarterwavelength. A support substrate is mounted on the DBR, a growthsubstrate is removed, an n-type layer and an active layer are thereafterremoved by dry etching to expose the p-type layer, and a p-typeelectrode is formed on the exposed p-type layer. In the semiconductorstructure described in this document, the dielectric layer having highreflectance is directly formed on the overall surface of the p-typecontact layer, and hence a surface of the p-type contact layer oppositeto the dielectric layer must be partially exposed for forming the p-typeelectrode thereon. However, a p-type nitride semiconductor layer hasextremely high resistance, as sufficiently known in this technicalfield. Therefore, a current cannot laterally diffuse from the portionprovided with the electrode. Even if the current slightly diffuses,resistance is extremely increased. Further, two electrodes must beformed on one side in this structure, to result in problems identical tothe above.

A vertical resonator surface emission laser device disclosed in JapanesePatent Laying-Open No. 2004-119831 includes a DBR, consisting of aquarter-wavelength multilayer semiconductor structure of Si-doped n-typeAlAs/AlGaAs, formed on a semiconductor substrate made of n-type GaAs. Inorder to implement a DBR having a structure similar to that of this DBRin a nitride semiconductor light-emitting device, a GaN substrate or anSiN substrate is generally employed as a conductive substrate. However,both of GaN and SiN are extremely high-priced and not suitable for alow-priced LED. In order to form the DBR by a multilayer structure ofGaN and AlGaN formable by epitaxy on the GaN or SiN substrate, thelayers must be extremely multicyclically grown due to small refractiveindex difference, and it is difficult to construct the DBR due tocracking or the like. In addition, the quality of an active layer grownon such a DBR is so inferior that internal quantum efficiency isreduced.

National Patent Publication Gazette No. 2008-506259 discloses atechnique of forming a DBR consisting of conductive ZnSSe and anMgs/ZnCdSe superlattice on a conductive GaAs substrate and welding theDBR to a nitride semiconductor layer provided on a sapphire substrate bywafer bonding. When the welding is performed without employing anadhesive, however, the surfaces of both wafers must indispensably beplanar, and the wafer bonding cannot be performed if the surface ofeither wafer is slightly irregularized. In the case of an actual nitridesemiconductor, waste or the like coming off a reactor frequently adheresto the surface of an epiwafer during epitaxy, and it is difficult tocompletely remove waste from the wafer.

Japanese Patent Laying-Open No. 2006-054420 discloses a light-emittingdevice having no vertical electrode structure but including a mesh DBRreflecting layer formed on a p layer of a flip chip light-emittingdevice and a contact electrode formed on a portion not provided with themesh DBR reflecting layer. The mesh DBR reflecting layer is made of anitride semiconductor. However, it is difficult to prepare a DBR from anitride semiconductor as hereinabove described, and even if such a DBRcan be prepared, no current is injected into a DBR region due to highresistance, and an injection area is reduced. Consequently, the currentdensity is increased to reduce luminous efficiency. If the contactelectrode portion has low reflectance, light extraction efficiency isalso reduced. While this document lists Ag, Ni, Al, Ph, Pd, Ir, Ru, Mg,Zn, Pt, Au etc. as exemplary materials for an ohmic contact layer, thesematerials have low reflectance except Ag and Al. Al having highreflectance cannot be brought into ohmic contact with a p-typesemiconductor layer, but increases resistance. If Ag is employed as thematerial for the ohmic contact layer, electromigration takes place tocause a short circuit upon migration to an n side, and hence thisstructure is extremely problematic in reliability.

As hereinabove described, there has hitherto been implemented no nitridesemiconductor light-emitting device excellent in internal quantumefficiency, light extraction efficiency and driving voltage as well asin mass productivity.

SUMMARY OF THE INVENTION

The present invention has been proposed in consideration of theaforementioned problems, and an object thereof is to provide a nitridesemiconductor light-emitting device capable of employing a verticalelectrode structure and excellent in internal quantum efficiency, lightextraction efficiency and driving voltage as well as in massproductivity and a method of manufacturing the same.

The present invention provides a nitride semiconductor light-emittingdevice including a reflecting layer made of a dielectric material, atransparent conductive layer, a p-type nitride semiconductor layer, alight emitting layer and an n-type nitride semiconductor layer in thisorder, and a nitride semiconductor light-emitting device including asupport substrate, a reflecting layer made of a dielectric material, atransparent conductive layer, a p-type nitride semiconductor layer, alight emitting layer and a n-type nitride semiconductor layer in thisorder.

The transparent conductive layer is preferably made of a conductivemetal oxide or an n-type nitride semiconductor. The reflecting layermade of a dielectric material preferably has a multilayer structureobtained by alternately stacking a layer made of a dielectric materialhaving a high refractive index and a layer made of a dielectric materialhaving a low refractive index. The reflecting layer made of a dielectricmaterial preferably has reflectance of 80 to 100% with respect to lightemitted from the light emitting layer. The thickness of the reflectinglayer made of a dielectric material is preferably set to 0.2 to 5 μm.

The surface on the side provided with the reflecting layer made of adielectric material is preferably planar in the surfaces of a nitridesemiconductor layer consisting of the p-type nitride semiconductorlayer, the light emitting layer and the n-type nitride semiconductorlayer, and the surface opposite to the side provided with the reflectinglayer made of a dielectric material is preferably irregularized in thesurfaces of the nitride semiconductor layer.

In the nitride semiconductor light-emitting device according to thepresent invention, the length of the transparent conductive layer in adirection perpendicular to the thickness direction is preferablyrendered smaller than the length of the p-type nitride semiconductorlayer in a direction perpendicular to the thickness direction, and thereflecting layer made of a dielectric material is preferably in contactwith both side surfaces of the transparent conductive layer and asurface of the transparent conductive layer closer to the reflectinglayer made of a dielectric material and further in contact with a partof a surface of the p-type nitride semiconductor layer closer to thetransparent conductive layer. The part of a surface is a surface whichis not in contact with the transparent conductive layer.

The reflecting layer made of a dielectric material preferably has athrough-port passing through the reflecting layer in the thicknessdirection in a region located immediately under the transparentconductive layer. The p-type nitride semiconductor layer preferablyincludes a current blocking region formed in contact with thetransparent conductive layer. In this case, the through-port provided inthe reflecting layer made of a dielectric material is preferablypositioned immediately under the current blocking region.

The nitride semiconductor light-emitting device according to the presentinvention may have a eutectic bonding layer of a single- or multilayerstructure made of a metal including a eutectic bonding metal or an alloycontaining the same between the support substrate and the reflectinglayer made of a dielectric material. The nitride semiconductorlight-emitting device may have an adhesion layer between the reflectinglayer made of a dielectric material and the eutectic bonding layer. Thesupport substrate may be a substrate made of a plated metal or alloy.

The present invention also provides a method of manufacturing a nitridesemiconductor light-emitting device including a support substrate, areflecting layer made of a dielectric material, a transparent conductivelayer, a p-type nitride semiconductor layer, a light emitting layer andan n-type nitride semiconductor layer in this order, including the stepsof (A) stacking the n-type nitride semiconductor layer, the lightemitting layer and the p-type nitride semiconductor layer on a growthsubstrate in this order, (B) forming the transparent conductive layer onthe surface of the p-type nitride semiconductor layer, (C) forming thereflecting layer made of a dielectric material on an exposed surface ofan obtained laminate, (D) stacking the support substrate, (E) removingthe growth substrate, and (F) obtaining a plurality of nitridesemiconductor light-emitting devices by performing chip division.

The method of manufacturing a nitride semiconductor light-emittingdevice according to the present invention preferably further includes astep (G) of partially exposing the transparent conductive layer byforming a through-port passing through the reflecting layer in thethickness direction in the reflecting layer made of a dielectricmaterial after the step (C). In this case, the through-port ispreferably formed by etching, and the transparent conductive layerpreferably functions as an etching stopper layer in etching. Further,the method of manufacturing a nitride semiconductor light-emittingdevice preferably further includes a step (H) of exposing the reflectinglayer made of a dielectric material by forming recesses substantially ata constant interval from the side of the n-type nitride semiconductorlayer between the steps (E) and (F).

The method of manufacturing a nitride semiconductor light-emittingdevice according to the present invention preferably further includes astep (I) of irregularizing the surface of the n-type nitridesemiconductor layer after the step (E).

When forming the aforementioned recesses, the chip division ispreferably performed on any positions on the bottom surfaces of therecesses in the step (F).

According to the present invention, a nitride semiconductorlight-emitting device of a vertical electrode structure or a one-sidetwo-electrode structure excellent in internal quantum efficiency, lightextraction efficiency and driving voltage as well as in massproductivity can be provided.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view showing a first embodiment of anitride semiconductor light-emitting device according to the presentinvention;

FIGS. 2 to 7 are schematic sectional views showing a method ofmanufacturing the nitride semiconductor light-emitting device shown inFIG. 1;

FIG. 8 is a schematic sectional view showing a second embodiment of anitride semiconductor light-emitting device according to the presentinvention; and

FIG. 9 is a schematic sectional view showing a nitride semiconductorlight-emitting device fabricated in Example 4, and FIG. 10 is aschematic sectional view of a nitride semiconductor light-emittingdevice including an adhesion layer according to the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention are now described in detail withreference to the drawings.

First Embodiment

FIG. 1 is a schematic sectional view showing a first embodiment of anitride semiconductor light-emitting device according to the presentinvention. The nitride semiconductor light-emitting device shown in FIG.1 has a multilayer structure obtained by stacking a support substrate101; a eutectic bonding layer 104 consisting of a second bonding layer102 and a first bonding layer 103; a reflecting layer 105 made ofdielectric materials; a transparent conductive layer 106; a p-typenitride semiconductor layer 109 consisting of a p-type GaN layer 107 anda p-type AlGaN layer 108; a light emitting layer 110; and an n-typenitride semiconductor layer 111 made of n-GaN in this order. A firstelectrode (n-side electrode) 112 is formed on the n-type nitridesemiconductor layer 1 1 1 while a second electrode (p-side electrode) 113 is formed on a surface of the support substrate 101 opposite to theeutectic bonding layer 104, so that the nitride semiconductorlight-emitting device has a vertical electrode structure.

Thus, the nitride semiconductor light-emitting device according to thefirst embodiment includes a multilayer structure of the reflecting layer105 made of dielectric materials and the transparent conductive layer106 between the support substrate 101 and the p-type nitridesemiconductor layer 109. According to this structure, a current can beefficiently injected into the overall light-emitting device through thetransparent conductive layer 106, whereby resistance can be reduced.Further, light emitted from the light emitting layer 110 toward thesupport substrate 101 can be efficiently reflected by the reflectinglayer 105 made of dielectric materials, whereby light extractionefficiency can be improved. While the quality of an active layer grownon a DBR is reduced to reduce internal quantum efficiency when the DBRis prepared by crystal growth, a DBR according to the present inventionexerts no influence on crystals. In other words, crystal growth can beperformed with a layer structure and growth conditions improving crystalquality according to the present invention, whereby internal quantumefficiency can be increased. Further, the transparent conductive layer106 is formed substantially on the overall surface of the p-type GaNlayer 107, whereby resistance is not increased but a driving voltage canbe reduced, dissimilarly to a case of partially exposing a p-type layerand forming an electrode on the exposed portion as described in JapanesePatent Laying-Open No. 2003-234542.

The reflecting layer 105, not particularly restricted so far as the sameis constituted of a dielectric material and has excellent reflectancewith respect to the light emitted from the light emitting layer 110,preferably has a multilayer structure obtained by alternately stacking alayer made of a dielectric material having a high refractive index and alayer made of a dielectric material having a low refractive index, sothat the reflecting layer 105 has high reflectance with respect to theemitted light. The dielectric material having a high refractive index isa dielectric material having a refractive index of about 1.7 to 3,preferably about 2 to 3 at an emission wavelength of 450 nm of theemitted light, such as SiN (having a refractive index of 2.1), TiO₂(having a refractive index of 2.4 to 3), GaN (having a refractive indexof 2.4), Ta₂O₃ or Ta₂O₅ (having a refractive index of 2.2 to 2.3), Nb₂O₅(having a refractive index of 2.3), ZrO, ZrO₂, CeO, Al₂O₃ or CeF₃, forexample. The dielectric material having a low refractive index is adielectric material having a refractive index of about 1 to 2,preferably about 1 to 1.8 at the emission wavelength of 450 nm of theemitted light, such as SiO₂ (having a refractive index of 1.47), MgF₂(having a refractive index of 1.38), CaF₂ (having a refractive index of1.43), Al₂O₃ or CeF₃, for example. Al₂O₃ or CeF₃ having an intermediaterefractive index can be employed for both of the layers having a highrefractive index and the layers having a low refractive index. When thereflecting layer 105 has the multilayer structure obtained byalternately stacking the layer made of a dielectric material having ahigh refractive index and the layer made of a dielectric material havinga low refractive index, the dielectric materials are so selected thatthe refractive index of the former is larger than that of the latter.

Assuming that one layer made of a dielectric material having a highrefractive index and one layer made of a dielectric material having alow refractive index form one period, the number of periods of themultilayer structure included in the reflecting layer 105 is notparticularly restricted. In consideration of improvement in reflectance,layers closer to the support substrate 101 and the transparentconductive layer 106 shown as the lowermost and uppermost layers in FIG.1 respectively are preferably formed by the layer made of a dielectricmaterial having a high refractive index and the layer made of adielectric material having a low refractive index respectively.

In order to attain more excellent reflectivity with respect to lightvertically incident upon the reflecting layer 105, the thickness of eachof the layers made of dielectric materials having high and lowrefractive indices constituting the reflecting layer 105 is preferablyset as follows:

Wavelength [nm] of light incident upon reflecting layer (wavelength [nm]of light emitted from light emitting layer)×(refractive index oflayer)/4 [nm]

When the layer made of a dielectric material having a high refractiveindex are made of SiN and the wavelength of the light emitted from thelight emitting layer 110 is 450 nm, for example, the thickness of thelayer made of SiN is preferably set to about 53 nm.

In order to attain excellent reflectance also with respect to lightobliquely incident upon the reflecting layer 105, the reflecting layer105 may further include a multilayer structure portion constituted oflayers made of dielectric materials having high and low refractiveindices respectively with thicknesses different from the above, inaddition to a multilayer structure portion constituted of layers havingthicknesses calculated from the above formula.

The total thickness of the reflecting layer 105, depending on the numberof periods of the multilayer structure and not particularly restricted,can be set to 0.2 to 5 nm, for example. While a method of manufacturinga nitride semiconductor light-emitting device according to the presentinvention described later preferably includes a step of forming recessesreaching the reflecting layer 105 by etching (dry etching, for example)from the side of the n-type nitride semiconductor layer 111, thereflecting layer 105 preferably functions as an etching stopper layer inthis etching and the thickness of the reflecting layer 105 is preferablyset to 0.2 to 5 nm, so that the reflecting layer 105 functions as theetching stopper layer.

The reflecting layer 105 preferably has reflectance of 80 to 100%,preferably 90 to 100% with respect to the light emitted from the lightemitting layer 110.

The transparent conductive layer 106, stacked on the aforementionedreflecting layer 105 made of dielectric materials, is preferably made ofa material having excellent conductivity. A conductive metal oxide suchas ITO (indium tin oxide), IZO (indium zinc oxide) or In₂O₃ (indiumoxide), for example, can be employed as such a conductive material.Alternatively, an n-type nitride semiconductor (n-typeAl_(x)In_(y)Ga_(1-x-y)N (0≦x≦1 and 0≦y≦1), for example) may be employed.The n-type nitride semiconductor is advantageously employed in suchpoints that a film thereof can be continuously grown in an MOCVDapparatus and the same has higher transmittance with respect to thelight of 450 nm in wavelength as compared with ITO or the like. Thethickness of the transparent conductive layer 106, not particularlyrestricted, can be set to 50 to 1000 nm, for example, and is preferably80 to 500 nm in consideration of improvement in transmittance.

According to the first embodiment, the lateral length (length in adirection perpendicular to the thickness direction) of the transparentconductive layer 106 is rendered smaller than the lateral length (lengthin a direction perpendicular to the thickness direction) of the p-typenitride semiconductor layer 109, more specifically the p-type GaN layer107, stacked thereon, so that the reflecting layer 105 covers both sidesurfaces of the transparent conductive layer 106 and the surface closerto the reflecting layer 105. The reflecting layer 105 is formed to be incontact with portions not in contact with the transparent conductivelayer 106 in the surface of the p-type GaN layer 107 closer to thetransparent conductive layer 106. According to this structure, endportions of the transparent conductive layer 106 and a P-N junction canpreferably be separated from each other, for preventing leakage.Further, the reflecting layer 105 made of dielectric materials canpreferably function as the etching stopper layer in the dry etching forforming the recesses for chip division.

The nitride semiconductor light-emitting device according to the firstembodiment has a current blocking region 114 formed in the p-type GaNlayer 107 to be in contact with the transparent conductive layer 106.Reduction in light extraction efficiency can be prevented by forming thecurrent blocking region 114 and arranging the first electrode 112 on aposition located immediately above the same.

According to the first embodiment, further, the reflecting layer 105 hasa through-port 115 passing through the reflecting layer 105 in thethickness direction in a portion located immediately under thetransparent conductive layer 106. A conductive material constituting thefirst bonding layer 103 arranged under the reflecting layer 105 isembedded in the through-port 115. The through-port 115 has an annularshape as viewed from above the nitride semiconductor light-emittingdevice. The annular through-port 115 is preferably formed to be withinthe range of the current blocking region 114 as viewed from above thenitride semiconductor light-emitting device. The annular through-port115 is preferably provided in the reflecting layer 105, so that thetransparent conductive layer 106 and the first bonding layer 103 can beconducted with low resistance. The width (W1 in FIG. 1) of the annularthrough-port 115, not particularly restricted, can be set to 0.5 to 50μm, for example, and is preferably 1 to 30 μm, so that the through-port115 does not jut out from the current blocking region 114 and is formedwith an excellent yield.

The nitride semiconductor light-emitting device according to the presentinvention preferably includes the current blocking region 114 and thethrough-port 115, which may be omitted, in consideration of improvementin light extraction efficiency and reduction in resistance.

Structures and materials well known in the art can be applied to thep-type nitride semiconductor layer 109, the light emitting layer 110 andthe n-type nitride semiconductor layer 111 respectively. The surface ofthe n-type nitride semiconductor layer 111 is preferably irregularizedas shown in FIG. 1, in order to improve the light extraction efficiency.The light emitting layer 110 can have a multiple quantum well structureprepared by alternately stacking well layers and barrier layers havingband gaps different from each other, for example.

A surface (surface of the n-type nitride semiconductor layer 111provided with the first electrode 112) of a nitride semiconductor layerconsisting of the p-type nitride semiconductor layer 109, the lightemitting layer 110 and the n-type nitride semiconductor layer 111opposite to the side provided with the reflecting layer 105 made ofdielectric materials is preferably irregularized. Thus, the lightextraction efficiency can be improved. Further, the surface (surface ofthe p-type nitride semiconductor layer 109 provided with the reflectinglayer 105 made of dielectric materials) of the nitride semiconductorlayer provided with the reflecting layer 105 made of dielectricmaterials is preferably planarized, in consideration of improvement inreflectance.

The support substrate 101 can be prepared from Si, GaAs, SiC, GaP, ametal or an alloy, for example.

The method of manufacturing the nitride semiconductor light-emittingdevice shown in FIG. 1 is now described with reference to FIGS. 2 to 7.While a case of obtaining three light-emitting devices from one wafer isdescribed with reference to FIGS. 2 to 7, the number of light-emittingdevices obtained from one wafer is not particularly restricted in thepresent invention.

First, a buffer layer 202 made of GaN, an n-type nitride semiconductorlayer 111 consisting of an n-type GaN layer, a light emitting layer 110and a p-type nitride semiconductor layer 109 consisting of a p-typeAlGaN layer 108 and a p-type GaN layer 107 are grown on a growthsubstrate 201 such as a sapphire substrate, an SiC substrate or a GaNsubstrate, for example, in this order (step (A); see FIG. 2). Metalorganic chemical vapor deposition (MOCVD) or the like can be employed asthe growth method. Then, a photoresist mask provided with circularopenings at a constant pitch, for example, is formed on the p-type GaNlayer 107, in order to form current blocking regions 114. Then, portionsof the p-type GaN layer 107 exposed in the openings of the photoresistmask are increased in resistance by plasma application or the like,thereby forming the current blocking regions 114.

Then, the photoresist mask is removed, and a layer for formingtransparent conductive layers 106 is thereafter stacked on the overallsurface of the p-type GaN layer 107. When the transparent conductivelayers 106 are made of ITO or the like, this layer can be formed bysputtering or the like. When the transparent conductive layers 106 aremade of an n-type nitride semiconductor or the like, on the other hand,this layer can be formed by MOCVD or the like. Then, three photoresistmasks each having a prescribed shape (square or rectangular shape, forexample) are formed at a constant pitch. The photoresist masks arepreferably so arranged that the central positions thereof issubstantially aligned with those of the current blocking regions 114respectively. Then, a laminate provided with the transparent conductivelayers 106 at constant intervals is obtained by performing etching, asshown in FIG. 2 (step (B)).

Then, the photoresist masks are removed, and a reflecting layer 105having a multilayer structure of a layer made of a dielectric materialhaving a high refractive index and a layer made of a dielectric materialhaving a low refractive index, for example, is formed on the overallexposed surface of the laminate by MOCVD or the like (step (C); see FIG.3). Then, a photoresist mask having annular openings is formed, in orderto form annular through-ports 115. This photoresist mask is preferablyso aligned that the annular openings are within the ranges of thecurrent blocking regions 114. Then, portions of the reflecting layer 105located in the openings are removed by etching to expose the transparentconductive layers 106, thereby obtaining a laminate shown in FIG. 3(step (G)). At this time, the transparent conductive layers 106 canfunction as etching stopper layers when the same are formed by ITO, IZOor GaN. If no annular through-ports 115 are provided, the step (G) isunnecessary.

Then, the photoresist mask is removed, and a first bonding layer. 103 isformed on the overall exposed surface. The first bonding layer 103 isprovided in order to stack a support substrate 101 on the laminate byeutectic bonding. The first bonding layer 103 can be made of a eutecticbonding metal such as Au, AuSn, AuSi or AuGe, for example, or an alloycontaining any of these materials. In order to improve adhesive strengthbetween the first bonding layer 103 and the reflecting layer 105, anadhesion layer 104 see FIG. 10) may be formed on the surface of thereflecting layer 105 in advance of the formation of the first bondinglayer 103. The adhesion layer can be provided in a well-known structuresuch as a multilayer structure of a Ti layer and a Pt layer, forexample. Then, the support substrate 101 is prepared, and a secondbonding layer 102 is formed on the surface thereof (see FIG. 4). Aeutectic bonding metal constituting the second bonding layer 102 is notparticularly restricted, so far as the same is eutectic-bondable to theeutectic bonding metal constituting the first bonding layer 103. Then,the laminate having the growth substrate 201 and a laminate having thesupport substrate 101 are bonded to each other by eutectic-bonding thefirst and second bonding layers 103 and 102 to each other, so that thesupport substrate 101 is stacked on the laminate having the growthsubstrate 201 (step (D)). The eutectic bonding layer 104 shown in FIG. 1consists of the first and second bonding layers 103 and 102.

Then, the growth substrate 201 is removed (step (E); see FIG. 5). Whenformed by a sapphire substrate, an SiC substrate or a GaN substrate, thegrowth substrate 201 can preferably be separated/removed by laserseparation with laser beams 203.

In a subsequent step, three photoresist masks are formed on the exposedn-type nitride semiconductor layer 111 at a constant pitch. Thephotoresist masks are preferably so arranged that the central positionsthereof is substantially aligned with those of the transparentconductive layers 106. Then, recesses 601 are formed from the side ofthe n-type nitride semiconductor layer 111 by dry etching or the like,to expose the reflecting layer 105 (step (H); see FIG. 6). The recesses601 are preferably formed in order to simplify chip division.

Then, the photoresist masks are removed, and the exposed surface of then-type nitride semiconductor layer 111 is irregularized (step (I); seeFIG. 6). The surface of the n-type nitride semiconductor layer 111 isnot necessarily but preferably irregularized, in order to improve thelight extraction efficiency. Then, first electrodes 112 are formed onthe irregularized surface of the n-type nitride semiconductor layer 111,while a second electrode 113 is formed on the back surface of thesupport substrate 101 (see FIG. 7). The first electrodes 112 arepreferably formed to be within the ranges of the current blockingregions 114, so that reduction in light extraction efficiency can beprevented. Finally, three nitride semiconductor light-emitting devicesare obtained by performing chip division (step (F); see FIG. 7). Thechip division is preferably performed on any positions (those of dottedlines shown in FIG. 7, for example) of the bottom surfaces of therecesses 601 (i.e., exposed surface portions of the reflecting layer105).

Second Embodiment

FIG. 8 is a schematic sectional view showing a second embodiment of anitride semiconductor light-emitting device according to the presentinvention. The nitride semiconductor light-emitting device shown in FIG.8 is different from the nitride semiconductor light-emitting deviceshown in FIG. 1 in a point employing a plating underlayer 803 and aplating layer 801 in place of the eutectic bonding layer 104, thesupport substrate 101 and the second electrode 113 in the nitridesemiconductor light-emitting device shown in FIG. 1. In other words, thenitride semiconductor light-emitting device shown in FIG. 8 has amultilayer structure obtained by stacking the plating layer 801; theplating underlayer 803; a reflecting layer 805 made of dielectricmaterials; a transparent conductive layer 806; a p-type nitridesemiconductor layer 809 consisting of a p-type GaN layer 807 and ap-type AlGaN layer 808; a light emitting layer 810; and an n-typenitride semiconductor layer 811 made of n-GaN in this order. A firstelectrode (n-side electrode) 812 is formed on the n-type nitridesemiconductor layer 811. In the second embodiment, the plating layer 811functions both as a support substrate and a p-side electrode. Therefore,the nitride semiconductor light-emitting device shown in FIG. 8 also hasa vertical electrode structure. A current blocking region 814 is formedin the p-type GaN layer 807, similarly to the first embodiment. Thenitride semiconductor light-emitting device having this structure canalso attain effects similar to those of the first embodiment.

Also in the second embodiment, the reflecting layer 805 has an annularthrough-port 815, an the positional relation between the through-port815, the current blocking region 814 and the first electrode 812 issimilar to that in the first embodiment. In the second embodiment, aconductive material constituting the plating underlayer 803 is embeddedin the through-port 815.

In the second embodiment, the plating underlayer 803 can be made of awell-known material such as Au, Ni, Cu, Sn, Pd, Ti or W, for example.The thickness of the plating underlayer 803 is not particularlyrestricted, so far as the same can fill up the annular through-port 815.

The plating layer 801 can be formed by Cu, Ni, Au or an alloy containingany of these metals, for example, and the thickness thereof can be setto 30 to 500 μm, for example, preferably 70 to 200 μm. The plating layer801 formed by plating is so employed as the support substrate that thesupport substrate can be formed with an excellent yield also in a caseof preparing a light-emitting device having a large area. In the case ofemploying the plating layer 801 as the support substrate, further, thesupport substrate can be directly stacked by forming the platingunderlayer 803 on the reflecting layer 805 and forming the plating layer801 thereon, more advantageously as compared with a method of formingtwo bonding layers, bonding the same to each other by eutectic bondingand stacking a support substrate.

EXAMPLES

While the present invention is now described in more detail withreference to Examples, the present invention is not restricted to theseExamples.

Example 1

A nitride semiconductor light-emitting device having the structure shownin FIG. 1 was fabricated by the following method, as described withreference to FIGS. 2 to 7: First, a buffer layer 202 made of GaN; ann-type nitride semiconductor layer 111 consisting of an n-type GaN layerhaving a thickness of 4 μm; a light-emitting layer 110 (having athickness of 100 nm) which is an MQW structure consisting of six periodsof GaN barrier layer and InGaN well layer; and a p-type nitridesemiconductor layer 109 consisting of a p-type AlGaN layer 108 (having athickness of 20 nm) and a p-type GaN layer 107 (having thickness of 80nm) were grown on a growth substrate 201 of sapphire in this order byMOCVD (step (A); see FIG. 2). Then, a photoresist mask having circularopenings of 90 μm in diameter at a pitch of 400 μm was formed on thep-type GaN layer 107, in order to form current blocking regions 114.Then, portions of the p-type GaN layer 107 exposed in the openings ofthe photoresist mask were increased in resistance by plasma application,thereby forming the current blocking regions 114.

Then, the photoresist mask was removed, and an ITO film having athickness of 100 nm was thereafter formed on the overall surface of thep-type GaN layer 107 by sputtering. Then, photoresist masks of 320 μm by320 μm were formed at a pitch of 400 μm, so that the central positionsthereof is substantially aligned with those of the current blockingregions 114. Then, the ITO film was etched with an etching solutioncontaining hydrochloric acid, thereby obtaining a laminate, providedwith transparent conductive layers 106, having the structure shown inFIG. 2 (step (B)).

Then, the photoresist masks were removed, and alloying was thereafterperformed in an atmosphere containing oxygen, thereby activating thep-type nitride semiconductor layer 109 and reducing the resistance ofand transparentizing the ITO film at the same time. Then, a reflectinglayer 105 was formed by stacking seven periods of SiO₂ layer (76 nmthickness)/SiN layer (53 nm thickness) by MOCVD (step (C); see FIG. 3).In this step, the first SiO₂ layer was stacked at the start, and theseventh SiN layer was finally stacked. Then, a photoresist mask providedwith annular openings (each having an outer diameter of 70 μm and awidth (opening width) of 3 μm) at a pitch of 400 μm was formed on thereflecting layer 105, in order to form annular through-ports 115. Atthis time, the photoresist mask was so aligned that the annular openingswere within the ranges of the current blocking regions 114 each having adiameter of 90 μm. Then, SiO₂ and SiN located in the annular openingswere removed by performing dry etching with CHF₃ to expose thetransparent conductive layers 106 made of ITO, thereby obtaining alaminate having the structure shown in FIG. 3 (step (G)). The selectionratio between SiO₂ and SiN, and ITO was at least 5 in the dry etchingwith CHF₃, and hence the ITO film functioned as an excellent etchingstopper layer.

Then, the photoresist mask was removed, a Ti film having a thickness of200 nm and a Pt film having a thickness of 100 nm were formed toconstitute an adhesion layer, and an Au film (having a thickness of 1000nm) was thereafter formed as a first bonding layer 103. Then, an Sisubstrate was prepared as a support substrate 101, and a Ti film havinga thickness of 200 nm, a Pt film having a thickness of 100 nm, an Aufilm having a thickness of 500 nm and an AuSn film having a thickness of3 μm were formed on the surface of the support substrate 101 in thisorder, thereby constituting a second bonding layer 102 (see FIG. 4).Then, the laminate having the growth substrate 201 and a laminate havingthe support substrate 101 were bonded to each other by eutectic-bondingthe first bonding layer 103 and the second bonding layer 102 to eachother by thermocompression bonding, thereby stacking the supportsubstrate 101 on the laminate having the growth substrate 201 (step(D)).

Then, the growth substrate 201 was separated by applying laser beams 203from the back surface of the growth substrate 201 (step (E); see FIG.5), and a damage layer was thereafter removed from the separated surfaceby dry etching.

Then, photoresist masks of 340 μm by 340 μm were formed on the exposedn-type nitride semiconductor layer 111 at a pitch of 400 μm, so that thecentral positions thereof is substantially aligned with those of thetransparent conductive layers 106. Then, recesses 601 were formed fromthe side of the n-type nitride semiconductor layer 111 by dry etching,to expose the reflecting layer 105 (step (H); see FIG. 6).

Then, the photoresist masks were removed, and the exposed surface of then-type nitride semiconductor layer 111 was irregularized in the form ofhexagonal pyramids with KOH (step (I); see FIG. 6). Then, firstelectrodes 112 of Ti/Au were formed on the irregularized surface of then-type nitride semiconductor layer 111 by lift-off with a photoresistmask (see FIG. 7). At this time, the first electrodes 112 were formed tobe within the ranges of the current blocking regions 114. The diameterof the first electrodes 112 was set to 70 μm, so that the firstelectrodes 112 were still within the ranges of the current blockingregions 114 having the diameter of 90 μm even if slight misalignmenttook place. Then, a second electrode 113 of Ti/Au was formed on the backsurface of the support substrate 101 (see FIG. 7). Finally, nitridesemiconductor light-emitting devices were obtained by performing chipdivision along positions corresponding to those shown in dotted lines inFIG. 7 (step (F); see FIG. 7).

The light output and the driving voltage of each nitride semiconductorlight-emitting device according to Example 1 obtained in theaforementioned manner were 25 mW and 3.2 V respectively.

Example 2

A nitride semiconductor light-emitting device according to Example 2 wasobtained similarly to Example 1, except that a reflecting layer 105 wasprepared by forming three periods of SiO₂ layer (102 nm thickness)/SiNlayer (72 nm thickness) and thereafter forming seven periods of SiO₂layer (76 nm thickness)/SiN layer (53 nm thickness). The obtainednitride semiconductor light-emitting device exhibited excellentreflectance also with respect to light obliquely incident upon thereflecting layer 105, and was further improved in light extractionefficiency. The light output and the driving voltage of the nitridesemiconductor light-emitting device according to Example 2 were 26 mWand 3.2 V respectively.

Example 3

A nitride semiconductor light-emitting device according to Example 3having the structure shown in FIG. 8 was obtained by carrying out stepssimilar to those in Example 1 up to formation of an annular through-port815 in a reflecting layer 805, thereafter forming an Au film having athickness of 2 μm as a plating underlayer 803, thereafter forming aplating layer 801 of Cu having a thickness of 80 μm by electrolyticplating, and carrying out subsequent steps similarly to Example 1. Thelight output and the driving voltage of the nitride semiconductorlight-emitting device according to Example 3 were 25 mW and 3.2 Vrespectively.

Example 4

A nitride semiconductor light-emitting device according to Example 4having a structure shown in FIG. 9 was fabricated as follows: First, asapphire substrate having a surface irregularized in a 5 μm period ofprojections was prepared as a growth substrate 901. Each projection ofthe irregularized surface was-in the form of a truncated cone having acircular bottom surface or a convex lens, and had a trapezoidal,semicircular or semielliptic sectional shape. The diameter of theprojection (the length of the base of the sectional shape) was 2.5 μm.The shape and the size of the projection are not restricted to theseexamples. When the surface of a sapphire substrate has such a shape, theinterface between the sapphire substrate and a nitride semiconductorlayer formed thereon is irregularized, whereby light extractionefficiency can be improved. Further, lateral growth is prompted,threading dislocations can be suppressed, and a light-emitting devicehaving high internal quantum efficiency can be obtained.

Then, a buffer layer (not shown) of GaN; an n-type nitride semiconductorlayer 902 consisting of an n-type GaN layer having a thickness of 4 μm;a light emitting layer 903 (having a thickness of 100 nm) having an MQWstructure consisting of six periods of GaN barrier layer/InGaN welllayer; and a p-type nitride semiconductor layer 906 consisting of ap-type AlGaN layer 904 (having a thickness of 20 nm) and a p-type GaNlayer 905 (having a thickness of 80 nm) were grown on the irregularizedsurface of the aforementioned sapphire substrate in this order by MOCVD.

Then, an ITO film having a thickness of 200 nm was formed on the overallsurface of the p-type GaN layer 905 by sputtering. Then, a photoresistmask of about 230 μm by about 480 μm was formed at a pitch of 250 μm by500 μm. Then, the ITO film was etched with an etching solutioncontaining hydrochloric acid, thereby forming a transparent electrodelayer 907.

Then, the aforementioned photoresist mask was removed, and alloying wasthereafter performed in an atmosphere containing oxygen, therebyactivating the p-type nitride semiconductor layer 906 and reducing theresistance of and transparentizing the ITO film at the same time. Then,a photoresist mask of about 240 μm by about 490 μm for mesa etching wasformed at a pitch of 250 μm by 500 μm, and the p-type GaN layer 905, thep-type AlGaN layer 904, the light emitting layer 903 and the n-typenitride semiconductor layer 902 consisting of the n-type GaN layer werepartially etched by dry etching, thereby partially exposing the n-typeGaN layer.

Then, an SiO₂ layer having a thickness of 200 nm was formed as a part ofa reflecting layer 908, thereby reducing a critical angle of totalreflection. Then, four periods of SiO₂ layer having a thickness of 102nm and SiN layer having a thickness of 72 nm were formed to increasereflectance in a direction of about 25°. Then, seven periods of SiO₂layer having a thickness of 76 nm and SiN layer having a thickness of 53nm were formed to maximize the reflectance in the vertical direction.The reflecting layer 908 having such a multilayer structure was soformed as to increase the quantity of totally reflected light due to theinfluence by the critical angle, and to increase the reflectance withrespect to light emitted from the light emitting layer 903 having theMQW structure in all directions due to the combination of the periodicstructure maximizing the reflectance by interference in the obliquedirection of 25° and the periodic structure maximizing the reflectancein the vertical direction.

Then, a photoresist mask was formed for boring holes of about 30 μmφ inpositions for forming pad electrodes 910 and 920 respectively, and SiO₂and SiN were removed from portions not provided with the photoresistmask by performing dry etching with CBF₃ gas, thereby partially exposingthe ITO film and the n-type GaN layer. The selection ratio between SiO₂and SiN, and ITO was at least 5 in the dry etching with CBF₃, and hencethe ITO film functioned as an excellent etching stopper layer.Similarly, the selection ratio between SiO₂ and SiN, and the n-type GaNlayer was at least 5 in the dry etching with CHF₃, and hence the n-typeGaN layer also functioned as an excellent etching stopper layer.

Then, a photoresist mask for forming the pad electrodes 910 and 920 bylift-off was formed, and a Ti film having a thickness of 15 nm, an Mofilm having a thickness of 20 nm and an Au film having a thickness of500 nm were deposited and lifted off to simultaneously form the padelectrodes 910 and 920 on p- and n-sides. The light output and thedriving voltage of the light-emitting device prepared in this mannerwere 25 mW and 3.2 V respectively.

In the light-emitting device fabricated in the aforementioned manner, anITO electrode (transparent conductive layer 907) efficiently injects acurrent into the overall surface of the light-emitting device to reduceresistance while a multilayer film of SiO₂ and SiN has high reflectance,whereby light emitted from the light emitting layer 903 toward thereflecting layer 908 made of dielectric materials is efficientlyreflected, efficiently extracted toward the sapphire substrate side dueto the irregularized interface between the sapphire substrate and thenitride semiconductor layer, and efficiently extracted from the backsurface and the side surfaces of the sapphire substrate.

In the light-emitting device according to Example 4, the sapphiresubstrate may be mounted on a base of a frame or the like to extract thelight from the side surfaces thereof, or the pad electrodes 910 and 920may be mounted on the base with bumps or the like as in a flip chip, toextract the light from the back surface and the side surfaces of thesapphire substrate.

In general, the size of the pad electrode must be about 80 μmφ, whetherthe same are wire-bonded or flip-chip-bonded with bumps or the like,depending on the size of balls in ball bonding or the bumps. In general,further, the pad electrode is made of a material such as Au having lowreflectance. According to Example 4, the reflecting layer made ofdielectric materials is formed between the pad electrode having lowreflectance and the light emitting layer except the region of a centralhole of about 30 μmφ, whereby the light emitted from the light emittinglayer toward the pad electrode is reflected by the reflecting layer madeof dielectric materials except the region of the central hole of about30 μmφ. Therefore, light absorption by the pad electrode can beremarkably prevented.

When the chip size is reduced, most of the chip surface is covered withthe pad electrode having low reflectance since the pad electrode cannotbe reduced in size. Also in this case, however, a light-emitting devicehaving high light extraction efficiency can be prepared with noinfluence by the pad electrode having low reflectance, due to theformation of the reflecting layer made of dielectric material.

Although the present invention has been described and illustrated indetail, it is clearly understood that the same is by way of illustrationand example only and is not to be taken by way of limitation, the scopeof the present invention being interpreted by the terms of the appendedclaims.

1. A nitride semiconductor light-emitting device including a reflectinglayer made of a dielectric material, a transparent conductive layer, anda nitride semiconductor layer including a p-type nitride semiconductorlayer, a light emitting layer and an n-type nitride semiconductor layerin this order, wherein said reflecting layer made of a dielectricmaterial has a through-port passing through said reflecting layer in thethickness direction in a region located immediately under saidtransparent conductive layer.
 2. The nitride semiconductorlight-emitting device according to claim 1, including a supportsubstrate, said reflecting layer made of a dielectric material, saidtransparent conductive layer, said p-type nitride semiconductor layer,said light emitting layer and said n-type nitride semiconductor layer inthis order.
 3. The nitride semiconductor light-emitting device accordingto claim 2, further including a eutectic bonding layer having a single-or multilayer structure made of a metal including a eutectic bondingmetal or an alloy containing said metal between said support substrateand said reflecting layer made of a dielectric material.
 4. The nitridesemiconductor light-emitting device according to claim 3, furtherincluding an adhesion layer between said reflecting layer made of adielectric material and said eutectic bonding layer.
 5. The nitridesemiconductor light-emitting device according to claim 2, wherein saidsupport substrate is a substrate made of a plated metal or alloy.
 6. Thenitride semiconductor light-emitting device according to claim 1,wherein said transparent conductive layer is made of a conductive metaloxide.
 7. The nitride semiconductor light-emitting device according toclaim 1, wherein said transparent conductive layer is made of an n-typenitride semiconductor.
 8. The nitride semiconductor light-emittingdevice according to claim 1, wherein said reflecting layer made of adielectric material has a multilayer structure obtained by alternatelystacking a layer made of a dielectric material having a high refractiveindex and a layer made of a dielectric material having a low refractiveindex.
 9. The nitride semiconductor light-emitting device according toclaim 1, wherein said reflecting layer made of a dielectric material hasreflectance of 80 to 100% with respect to light emitted from said lightemitting layer.
 10. The nitride semiconductor light-emitting deviceaccording to claim 1, wherein a first surface of the nitridesemiconductor layer provided with said reflecting layer made of adielectric material is planar.
 11. The nitride semiconductorlight-emitting device according to claim 1, wherein a second surface ofthe nitride semiconductor layer opposite to a first surface of thenitride semiconductor layer.
 12. The nitride semiconductorlight-emitting device according to claim 1, wherein the length of saidtransparent conductive layer in a direction perpendicular to thethickness direction is smaller than the length of said p-type nitridesemiconductor layer in a direction perpendicular to the thicknessdirection, and said reflecting layer made of a dielectric material is incontact with both side surfaces of said transparent conductive layer anda surface of said transparent conductive layer closer to said reflectinglayer made of a dielectric material and further in contact with a partof a surface of said p-type nitride semiconductor layer closer to saidtransparent conductive layer, said part of a surface being not incontact with said transparent conductive layer.
 13. The nitridesemiconductor light-emitting device according to claim 1, wherein thethickness of said reflecting layer made of a dielectric material is 0.2to 5 μm.
 14. A nitride semiconductor light-emitting device including areflecting layer made of a dielectric material, a transparent conductivelayer, and a nitride semiconductor layer including a p-type nitridesemiconductor layer, a light emitting layer and an n-type nitridesemiconductor layer in this order, wherein said p-type nitridesemiconductor layer includes a current blocking region formed in contactwith said transparent conductive layer.
 15. The nitride semiconductorlight-emitting device according to claim 14, wherein said reflectinglayer made of a dielectric material has a through-port passing throughsaid reflecting layer in the thickness direction in a region locatedimmediately under said transparent conductive layer, and saidthrough-port provided in said reflecting layer made of a dielectricmaterial is positioned immediately under said current blocking region.16. A method of manufacturing a nitride semiconductor light-emittingdevice including a support substrate, a reflecting layer made of adielectric material, a transparent conductive layer, a nitridesemiconductor layer including a p-type nitride semiconductor layer, alight emitting layer and an n-type nitride semiconductor layer in thisorder, including the steps of: (A) stacking said n-type nitridesemiconductor layer, said light emitting layer and said p-type nitridesemiconductor layer on a growth substrate in this order; (B) formingsaid transparent conductive layer on the surface of said p-type nitridesemiconductor layer; (C) forming said reflecting layer made of adielectric material on an exposed surface of an obtained laminate; (D)stacking said support substrate; (E) removing said growth substrate; and(F) obtaining a plurality of nitride semiconductor light-emittingdevices by performing chip division; wherein the forming said reflectinglayer made of a dielectric material includes forming a through-portpassing through said reflecting layer in the thickness direction in aregion located immediately under said transparent conductive layer. 17.The method of manufacturing a nitride semiconductor light-emittingdevice according to claim 16, further comprising a step (G) of partiallyexposing said transparent conductive layer by forming a through-portpassing through said reflecting layer in the thickness direction in saidreflecting layer made of a dielectric material after the step (C). 18.The method of manufacturing a nitride semiconductor light-emittingdevice according to claim 17, wherein said through-port is formed byetching and said transparent conductive layer functions as an etchingstopper layer in the step (G).
 19. The method of manufacturing a nitridesemiconductor light-emitting device according to claim 16, furthercomprising a step (H) of exposing said reflecting layer made of adielectric material by forming recesses substantially at a constantinterval from the side of said n-type nitride semiconductor layerbetween the steps (E) and (F).
 20. The method of manufacturing a nitridesemiconductor light-emitting device according to claim 19, wherein saidchip division is performed on any positions on the bottom surfaces ofsaid recesses in the step (F).
 21. The method of manufacturing a nitridesemiconductor light-emitting device according to claim 16, furthercomprising a step (I) of irregularizing the surface of said n-typenitride semiconductor layer after the step (E).
 22. A method ofmanufacturing a nitride semiconductor light-emitting device including agrowth substrate, a nitride semiconductor layer including an n-typenitride semiconductor layer, a light emitting layer, and a p-typenitride semiconductor layer, a transparent conductive layer and areflecting layer made of a dielectric material in this order, includingthe steps of: (a) stacking said n-type nitride semiconductor layer, saidlight emitting layer and said p-type nitride semiconductor layer on saidgrowth substrate in this order; (b) forming said transparent conductivelayer on the surface of said p-type nitride semiconductor layer; (c)etching said transparent conductive layer, said p-type nitridesemiconductor layer, said light emitting layer and a part of said n-typenitride semiconductor layer to partially expose said n-type nitridesemiconductor layer; (d) forming said reflecting layer made of adielectric material on a surface of said transparent conductive layerand said p-type nitride semiconductor layer, and on an exposed surfaceof said n-type nitride semiconductor layer, the step of forming saidreflecting layer including: forming an SiO₂ layer having such athickness that a critical angle of total reflection is reduced; forminga periodic structure of SiO₂ layers and SiN layers, the periodicstructure maximizing the reflectance of light in the oblique directionof 25°; and forming a periodic structure of SiO₂ layers and SiN layers,the periodic structure maximizing the reflectance of light in thevertical direction; removing a part of said reflecting layer inpositions for forming pad electrodes; and (f) forming said padelectrodes, wherein the forming said reflecting layer made of adielectric material includes forming a through-port passing through saidreflecting layer in the thickness direction in a region locatedimmediately under said transparent conductive layer.